Building-integrated photovoltaic (BIPV) materials generally include materials that generate electricity through the use of solar cells (PV cells), and that are configured to be installed onto the roof or side of a building. Once installed, BIPV materials serve as protective roofing or siding materials and also generate electricity. Accordingly, it is desirable that BIPV materials be flexible and be capable of maintaining both their protective and electricity-generating characteristics for a long period of time, such as 10 years, 20 years, or even longer.
BIPV modules generally include a multi-layer top sheet overlying the solar cells, and a multi-layer back sheet underlying the solar cells. The top sheet and the back sheet are each configured to protect the solar cells from exposure to the elements, and particularly from exposure to water and water vapor, and are typically joined together by a process such as lamination. To accomplish this protective function, one or both of the top sheet and the back sheet may include a vapor barrier, which may itself be part of a separate multi-layer structure.
Two areas in which BIPV modules may be particularly susceptible to water incursion are at the edge portions of the multi-layer top sheet and back sheet, particularly in the vicinity of the vapor barrier(s). If water enters at these edge portions, it can penetrate between layers of the top sheet and/or back sheet, and compromise the mechanical and electrical stability of those structures. Accordingly, a BIPV module offering improved protection for the edge portions of the top sheet and back sheet would provide desirable improvement to the mechanical stability and longevity of the module.